1. Field of the Invention
The present invention relates generally to heating products, and in one of its aspects, to a cooking apparatus and a door therefor.
2. Description of the Prior Art
In the past, cooking large volumes of food of a consistently high quality has been a major problem, especially for fast food restaurants. The problem has been made worse because of the desirability of having some of the food preparation take place well in advance of the time for actually serving the final food product, and then freezing the partially prepared food.
Pizzas and french fries are among the most popular of all fast food items, and at the same time, present considerable difficulty in preparation. For example, a pizza is usually made with a thin pastry shell, and is topped with tomato paste, cheese and other toppings. The pizza will heat rapidly from surface heating. Many pizza ovens use stone or other low conductivity material for the product support area in order to limit the rate of heat transfer to the bottom of the pizza. If the bottom of the pizza heats too rapidly, then the crust blisters, lifting the surface of the pizza crust away from the heating surface. The denser dough between the blisters bakes far more slowly, causing the thin shell of the blisters to overbake in order to adequately cook the areas between the blisters. It is, therefore, desirable to bake pizzas relatively slowly to avoid this problem.
French fried potatoes have presented a similar problem since they also can be rapidly warmed by surface heating. Preparing the french fries in advance of the time they are actually to be served and then warming them also presents problems. Microwave heating warms the previously prepared french fries, but leaves them soggy and tasteless. Infrared heating of the previously prepared french fries browns and crisps the surfaces of the fries that are exposed to the incident radiation. Still air oven heating, on the other hand, dries the potatoes out before they become crisp or brown.
Many of the problems which existed in the past were solved by the cooking apparatus of U.S. Pat. No. 3,884,213 issued to Smith. The apparatus described by Smith utilized directed jets of temperature controlled gaseous fluids directly applied to food portions. In one arrangement, jets of air are swept over the product at a proper rate to heat all exposed surfaces.
The apparatus of Smith is particularly well suited for cooking large quantities of quickly prepared foods by use of a conveyor for transporting the food items through the heat transfer space. The problem arises when it is desired to cook more than a single type of food item in the same conveyor type cooking apparatus. For instance, many restaurants cook pizzas as their main product line but would also like to offer sandwiches, thin lasagna in a dish or bulk prepared food. A conveyor type cooking apparatus that would take six minutes to cook pizzas would only take two and one half minutes to cook an open face sandwich, and more than six minutes for some bulk prepared foods. To change the conveyor speed for different products or to change the cooking temperature would necessitate just cooking one type of food product at a time in a single cooking apparatus. Alternatively, the conveyor and heat could be set for the most rapidly cooking items, and the slower cooking items could be run through the apparatus multiple times, but this would require tremendous amounts of work. A system of multiple belts, such moving at a different speed, has also been suggested.
Oven doors, in the past, have generally been one of two types. One type of oven door would swing outward from one side of the door, the opposite side of the door hingedly engaging the cabinet of the cooking apparatus. The other type of door, common on ovens, would swing out from the top with the bottom of the door hingedly engaging the cabinet of the cooking apparatus. In both cases, the handle would be a simple grip attached to the edge of the door which opened away from the cabinet. Further, the door was also the primary input and output port for the cooking apparatus.
Oven doors which open outward expose the user to the hot inner surfaces of the doors. Further, in an apparatus to transfer heat to a product that utilizes turbulent rapidly moving hot air, the turbulent air is close to the outside of the oven and, when the door is opened outwards, hot air rushes over the user causing discomfort and a burn hazard. The escaping hot air also heats the surrounding work area, causing discomfort. Additionally, it accounts for considerable energy loss.